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6mt going down hills
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07-28-2012, 11:03 AM | #1 |
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6mt going down hills
so the other day i was driving with my dad in his car. we were going down a hill, so he put it in neutral (6mt). just as conversation, i told him "when i'm going down a hill i noticed that my mpg's are higher when i leave it in gear than when i put it in neutral for some reason."
he told me that someone had told him that on some cars it's actually bad to let it coast in neutral. now he knows absolutely nothing about cars, and it doesn't really sound like that can be true.. but has anyone heard anything like that ever? have i been ruining my car lol?
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07-28-2012, 11:05 AM | #2 |
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Fuel injection is shut off above a certain RPM at 0% throttle (which equates to coasting in gear). MPG is almost always higher in this scenario than coasting with the engine idling (and burning fuel). I find that my N52KP doesn't have a whole lot of engine braking compared to other engines I've had (probably partially because of Valvetronic).
Performance driving school will also teach you that you never disconnect the wheels from the engine like that for any period of time. They teach that you should ALWAYS have some kind of gear selected ready to apply power if necessary. |
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07-28-2012, 11:32 AM | #3 |
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this i was taught when i was around 10 year old driving LADA
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07-28-2012, 11:47 AM | #4 | |
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07-28-2012, 11:48 AM | #5 |
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Huh I coast in neutral all the time I don't think it's bad
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08-16-2012, 12:39 PM | #6 |
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08-16-2012, 01:09 PM | #9 |
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On the subject of gas usage
Its got and gas usage gauge on the display .
There is better control of the car when not in neutral which is one of the main reasons for having a manual. |
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08-16-2012, 01:10 PM | #10 |
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perhaps engine idling itself on neutral is bad for the engine.... ive heard this also. dont have a exact mechanical explaination... anyone?
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08-16-2012, 01:27 PM | #11 | |
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Last edited by AndreyT; 08-16-2012 at 01:38 PM.. |
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08-16-2012, 01:28 PM | #12 |
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I have learnt that coasting with clutch in will cause wear on your throw out bearing.
As for coasting in neutral... That is just poor drivin habits. Always be in control of your vehicle. Like it has already been said, coasting with modern efi in gear shuts off fuel flow. |
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08-16-2012, 01:54 PM | #13 | |||||||
I have to return some video tapes
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guess i was just being stupid.
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08-16-2012, 02:09 PM | #14 |
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Speaking of the throwout bearing
When you are at a stop put the car in neutral and let the clutch out
This does two things It reduces the wear on the throwout bearing and its safer as if you were in gear and accidentally had your foot slip off the clutch you would rear end the next guy or slip into the intersection on a red light. |
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08-16-2012, 05:30 PM | #17 |
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Basically all has been covered. But yes, coasting (with the engine not connected to the wheels) is from a safety point of view not good, and does often put more load on the brakes. From the point of view of mechanical troubles, only the release bearing takes a pounding if you are sitting with your foot on the depressed clutch pedal - even sitting at the lights or resting your foot on the clutch lightly while driving is not advised. Engine will be using more fuel too since it is not shutting the fuel supply off while running under compression alone. On the 330i instead of the temperature gauge we have the econometer, and it shows exactly how this functions.
Under engine braking approaching a stop it will be on zero fuel usage, then clutch in so as to not stall, and from the car still moving the needle will briefly climb until you are stationary. Coasting out of gear the needle sits at a low-ish consumption which is obviously lower as the speed increases, but why waste the fuel when you can be safer using engine braking... |
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